Blast furnace stove

ABSTRACT

A blast furnace stove is provided with a plate steel wall which partially divides said stove into a combustion chamber and a checker chamber. The checkerwork is supported on a plurality of interlocked grids, which in turn is supported on a plurality of interlocked girders secured to columns disposed in housings rigidly affixed to the floor of said checker chamber.

Oct. 9, 1973 United States Patent [191 Smith, Jr.

2,542,680 2/1951 Kinney et 432/217 3,488,041 1 1970 P ll t l. 432 217Marvin 0. Smith, Jr., Bethlehem, owe e a l A N a R P U F r T m S A m LVB .m M M U U Primary Examiner-Edward G. Favors [73] Assrgnee: BethlehemSteel Corporation, Attorney joseph J. O,Keefe Bethlehem, Pa.

[22] Filed: Aug. 15, 1972 [21] Appl. No.: 280,914

ABSTRACT A blast furnace stove is provided with a plate steel wall whichpartially divides said stove into a combustion chamber and a checkerchamber. The checkerwork is supported on a plurality of interlockedgrids, which in turn is supported on a plurality of interlocked girderssecured to columns dis posed in housings rigchecker chamber.

References Cited UNITED STATES PATENTS idly affixed to the floor of said1,860,368 Seaver 432/217 4 Claims, 6 Drawing Figures PATENTED OCT 9 I973sum 1m 2 BLAST FURNACE STOVE BACKGROUND OF THE INVENTION This inventionrelates to regenerative stoves for heating furnace combustion air, andmore specifically to improvements in blast furnace stoves.

Blast furnace stoves generally comprise an insulated cylindrical outershell with a dome-shaped top and a flat bottom. The interior of thestove is divided into two sections, viz. a combustion chamber and achecker chamber. In the two-pass type of stove, gas is burned in thecombustion chamber, which is made of refractory bricks, and passesupwardly to the dome. The hot products of combustion are then blowndownwardly through the checker chamber, which comprises a refractorycheckerwork having a plurality of flues therein, and exhausted into astack through a chimney flue connection disposed at a point near thebottom of the stove. After the checkerwork has reached the desiredtemperature, combustion is stopped and cold blast air is blown into thechecker chamber in the reverse direction. This air passes upwardlythrough the checkerwork, thereby becoming heated, passes downwardly inthe combustion chamber, and is supplied through a hot blast connectionto a blast furnace.

In the past, the checkerwork has been supported on a network ofhorizontally disposed grids with the grids in turn being supported onhorizontally disposed girders. The girders were supported on columnswhich rested on the stove floor, thereby providing a space below thegirders to which one or more chimney flue connections and one cold blastconnection were made.

Examination of the checkerwork supporting structure during periods whenthe stove is shut down frequently has shown that the bottom courses ofcheckers are prematurely severely damaged, resulting in the need forearly replacement of these courses.

In addition to the foregoing the supporting girders have occasionallybecome dislodged and columns have collapsed.

Furthermore, accelerated failure of the brick forming the combustionchamber has been discovered, particularly at points directly oppositethe point where the combustion gas is fed into the combustion chamberand ignited. This also results in the need for early replacement ofbrickwork.

It is an object of this invention to provide a regenerative stove havinga checkerwork supporting structure in which the bottom courses ofcheckers are not prematurely severely damaged.

It is a further object of this invention to provide a regenerative stovehaving means for preventing accelerated failure of the brick forming thecombustion chamber.

SUMMARY OF THE INVENTION I have discovered that damage to the bottomcourses of checkers and premature collapse of the girders and columnsare caused by shifting of the elements comprising the checker-supportingsystem,and that such shifting and consequent damage can be minimized byproviding a supporting system having the following characteristics.First, the bases of the columns are disposed in housings affixed to thefloor of the stove, thereby limiting shifting of the columns along thefloor. Secondly, the girders are all interlocked and secured to the topsof said columns by means to limit their movement. Thirdly, the gridswhich are supported on the girders are all interlocked.

I have also discovered that failure of the combustion chamber brick isdue to the hot combustion gases bypassing the checkers and passingdirectly through cracks in the combsution chamber wall, thereby notadding heat to the checker work prior to discharge out the chimney flueconnection. Likewise the cold blast air passes directly through the samecracks on the blowing cycle, thus bypassing the checkers and thereby notbecoming heated prior to discharge out the hot blast connection. Thisproblem can be eliminated by providing an upright, substantiallysemi-cylindrical steel plate between the combustion chamber wall and thechecker chamber.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation view of ablast furnace stove.

FIG. 2 is an enlarged sectional side elevation view showing details ofthe combustion chamber and checker supporting structure.

FIG. 3 is a portion of an enlarged sectional view through the lines 33of FIG. 2.

FIG. 4 is a side elevation view, partly in section, showing details ofthe checker supporting structure.

FIG. 5 is a sectional half plan view, through the lines 5-5 of FIG. 2,showing the interlocked girders and related structure.

FIG. 6 is a sectional half plan view, through the lines 6-6 of FIG. 2,primarily showing the interlocked grids.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, the blastfurnace stove of the invention broadly comprises a cylindrical steelouter shell 10 having a dome-shaped top 12 and a flat steel bottom 14having a concrete floor 15 thereon supporting refractory brick 17.Within the shell 10 is a combustion chamber 16 and a checker chamber 18.The checker chamber 18 comprises checkerwork 20 resting upon asupporting structure broadly designated as 22. Below the supportingstructure 22 is a space which communicates with a cold blast connection24 and at least one chimney flue connection 26.

The combustion chamber 16 is provided with a burner opening 28. Disposedabove the burner opening 28 is a hot blast connection 32. As shown indetail in FIGS. 2 and 3, the combustion chamber 16 is formed ofrefractory bricks 30. Disposed about the refractory bricks 30, in thevicinity of the burner opening 28, is a semi-cylindrical plate steelshell 34 comprising a lower section 36 and an upper section 38. Weldedto the inside of the lower section 36 is an annular plate 40 whichfrictionally engages the inside of the upper section 38 and serves as aguide therefor during expansion and contraction of said upper section 38during the heating and cooling cycles. The upper section 38 is heldsubstantially in place by the surrounding refractory bricks 30, and isinitially positioned so that there is a small distance 42 between thebottom edges thereof and the top edges of the lower section 36. Thisarrangement functions as a vertical thermal expansion joint.

The shell 34 is provided with a horizontal thermal expansion joint 44,shown more clearly in FIG. 3, comprising a split pipe 46 welded to eachside of a vertical split in the shell 34. Dust and brick residue areprevented from entering the pipe 46 by providing a vertical cover plate48, welded to one side only of the split in the shell and a horizontalcover plate 50, also welded to one side only of the split in the shell.The joint 44 is disposed in a space 52 provided in insulating brick 54,which brick fills the space between the checkers 20, the steel plate 34,and the steel outer shell 10.

As shown in FIG. 4, disposed on the stove bottom 14 and recessed in theconcrete 15 and brick 17 is a plurality of column housings 56. In eachhousing is disposed a leveling assembly 58 comprising a bearing plate 68and a bottom plate 62 interconnected by leveling screws 64. The housingis filled with a grout 66 after leveling of columns 56. As can be seen,the face of the bottom plate 62 is smaller than the cross-section of thehousing 56; thus, the bearing plate 60 is capable of limited movementwithin the housing 56. The space immediateiy above the leveling assembly58 is filled with a compressible refractory 67.

Each of a plurality of box-like columns 68 has its base welded to one ofthe bearing plates. Said columns 68 are adapted to provide a support fora plurality of interlocked girders 70, shown in detail in FIG. 5, andeach column comprises a top plate 72 welded to side plates 74.

The girders 70 are welded to means for limiting movement comprisingbox-like cap members 76. Each of said cap members 76 comprises a bearingplate 78 and side plates 80. Each cap member 76 fits over the top of acolumn 68 and is capable of limited movement in the horizontal planesince the side plates 80 are spaced slightly from the column side plates74.

As shown in FIG. 5, a pair of girders 70 is welded to each of the capmembers 76, and each girder is parallel to every other girder and to thecenterline of the burner opening 28. Each girder is spaced from theother girder forming the pair by a plurality of short spacer plates 82welded therebetween. Each pair of girders is spaced from adjacent pairsby spacer plates 84, bolted together at 86, for example, and welded tothe girders 70. In this manner, all of the girders 70 are interlockedand provide a support for grids 88, shown in detail in FIG. 6.

The grids 88 are thin plate members disposed perpendicularly to thegirders 70. A plurality of grids 88 is formed into a section by means ofspacers 9i) welded therebetween. The various sections are interlocked bymeans of bolts and spacer sleeves 92.

Immediately adjacent to the girders 70 and grids 88, and built into thebrick wall 54, are steel bumper T- plates 94. The T-plates 94 preventdamage to the wall 54 during expansion of the girders 70 and grids 88during heating.

The checkerwork rests on intermediate support ing means comprising caststeel shoes 21. The shoes 21 are supported by the grids 88, and areprovided with male projections which interlock with female connectionsprovided in the bottoms of the lowest row of checkers.

The operation of the subject blast furnace stoves is identical to thatof prior art two-pass blast furnace stoves. However, because of thedesign of the checkerwork supporting structure, shifting thereof duringthe heating and cooling cycles and consequent damage to the bottomcourses of checkers and collapsing of columns, girders and grids areminimized. In addition, because of the plate steel shell 34, bypassingof hot combustion gases during the heating cycle and the cold blastduring the reverse cycle is prevented, thereby preventing acceleratedfailure of thebrick forming the combustion chamber.

I claim:

1. A regenerative stove for heating combustion air, comprising:

a. an outer shell, substantially cylindrically shaped,

having first and second openings therein for passing cold air into saidstove and hot air out of said stove, said shell being lined withinsulating brick,

b. an upright, steel plate partially dividing said stove into acombustion chamber and a checker chamher, said steel plate being rigidlyaffixed at its side ends to said outer shell,

c. a refractory wall adjacent said plate providing an enclosure for saidcombustion chamber,

d. a third opening in said outer shell, for introducing combustion gasinto said combustion chamber,

e. a fourth opening in said outer shell, for removing combustion gasfrom said checker chamber,

f. a plurality of columns in said checker chamber, the bases of saidcolumns being disposed in housings affixed to the floor of said stove,

g. a plurality of interlocked girders,

h. limitedmovement means securing said girders to the tops of saidcolumns,

i. a plurality of interlocked grids resting upon said girders,

j. intermediate supporting means resting upon said grids, and

k. refractory checkerwork resting upon said intermediate supportingmeans.

2. A stove as recited in claim 1, in which steel bumper plates areembedded in the insulating brick wall adjacent to said grids.

3. A stove as recited in claim 1, in which said limitedmovement means(h) comprises a cap member rigidly affixed to a girder, said cap memberabutting the top of a column and having four downwardly disposed sides,each of said sides being in close proximityto a side of said column. d

4. A stove as recited in claim 1, in which the plate (b) is providedwith vertical and horizontal thermal expansion joints.

1. A regenerative stove for heating combustion air, comprising: a. anouter shell, substantially cylindrically shaped, having first and secondopenings therein for passing cold air into said stove and hot air out ofsaid stove, said shell being lined with insulating brick, b. an upright,steel plate partially dividing said stove into a combustion chamber anda checker chamber, said steel plate being rigidly affixed at its sideends to said outer shell, c. a refractory wall adjacent said plateproviding an enclosure for said combustion chamber, d. a third openingin said outer shell, for introducing combustion gas into said combustionchamber, e. a fourth opening in said outer shell, for removingcombustion gas from said checker chamber, f. a plurality of columns insaid checker chamber, the bases of said columns being disposed inhousings affixed to the floor of said stove, g. a plurality ofinterlocked girders, h. limited-movement means securing said girders tothe tops of said columns, i. a plurality of interlocked grids restingupon said girders, j. intermediate supporting means resting upon saidgrids, And k. refractory checkerwork resting upon said intermediatesupporting means.
 2. A stove as recited in claim 1, in which steelbumper plates are embedded in the insulating brick wall adjacent to saidgrids.
 3. A stove as recited in claim 1, in which said limited-movementmeans (h) comprises a cap member rigidly affixed to a girder, said capmember abutting the top of a column and having four downwardly disposedsides, each of said sides being in close proximity to a side of saidcolumn.
 4. A stove as recited in claim 1, in which the plate (b) isprovided with vertical and horizontal thermal expansion joints.